It is generally known that foam is filled in a hollow member formed in a closed cross section, such as a pillar of a vehicle, as a filling material, in order to prevent transmission of vibrations and noises of an engine of the vehicle or fluttering sounds of the vehicle to an interior of the vehicle.
Polymer foams comprising various kinds of resins and rubbers are used as the foam to be filled. The polymer foams are used for example in such a manner that prefoam of the polymer foams is set in an internal space of the hollow member before foamed and, then, the prefoam is foamed and crosslinked by application of heat and the like in a baking finish process of the hollow member, to thereby form the foam in the internal space of the hollow member, so as to fill up the internal space, without leaving any space therein.
For example, JP Laid-open (Unexamined) Patent Publication No. 2002-79955 proposed a space filling material comprising at least polymer, a foaming agent, and a cross-linking agent. It also proposed a space-filling-material fixing jig, formed of resin, for holding the space filling material securely in the interior space of an object to be filled.
JP Laid-open (Unexamined) Patent Publication No. Hei 10-95869 proposed cross-linking foam for reinforcing a vehicle body having the composition comprising 50-200 parts by weight of an inorganic filling material, 1-50 parts by weight of a thermally decomposable foaming agent, and 2-10 parts by weight of an organic peroxide per 100 parts by weight of diene synthetic rubber component.
After the components of the prefoam used for forming the foam are kneaded, the prefoam is molded to conform to a shape of the hollow member by an injection molding or by a press molding. However, in these molding processes, unwanted parts, such as runners in the injection molding and burrs in the press molding, are produced incidentally. Also, inferior goods may be produced due to a dimensional error and the like.
These unwanted parts and inferior goods are disposed by burning or by landfill.
In this prefoam (space filling material, cross-linking foam for reinforcing vehicle body, etc.), the foaming agent is decomposed by application of heat in the foaming process, to thereby produce acid. When the acid produced contacts with an inside surface of the hollow member to be filled up with the foam, rust may be formed in the inside surface of the hollow member.
To solve this problem, JP Laid-open (Unexamined) Patent Publication No. 2002-79955 proposed a space-filling-material fixing jig comprising a base for holding the space filling material, supporting legs projected from the base, and valved lugs extended at tip ends of the supporting legs. In use, the base is disposed in the internal space so that the space filling material can be held by the base. On the other hand, the valved lugs are engaged with the hollow member so that the space filling material can be spaced from the inside surface of the hollow member in the internal space of the hollow member to prevent the space filling material from contacting directly with the inside surface of the hollow member before the rustproofing process.
However, when the internal space of the hollow member is so narrow that a sufficient spacing cannot be provided between the space filling material and the inside surface of the hollow member, the space filling material and the inside surface of the hollow member may be put in direct contact with each other and, as a result, rust may still be formed in the inside surface of the hollow member.
Meanwhile, recycling of the unwanted parts and inferior goods can advantageously provide an improved yielding percentage and thus improved cost efficiency. The recycling of the unwanted parts and the inferior goods can impart, in addition to a heat history for original material to be kneaded, an additional heat history for the original material to be re-kneaded and molded. Due to this, a foam ratio of the foam produced by using the recycled material may be decreased at the sequent foaming, as compared with that of the foam produced by using the original material.
The foaming agent is partly decomposed by the application of heat in the kneading and molding processes to thereby produce acid. But, when organic peroxide is mixed to the foaming agent, the organic peroxide is not radical decomposed but is ion-decomposed. As a result, the cross-linking of the foam composition does not proceed in the foaming process, so that sufficient foam of the foam is not obtained.
It is an object of the present invention to provide filling foam composition capable of providing excellent rustproofing and also suppressing decrease of a foam ratio of the foam composition even when reusing unwanted parts thereof and inferior goods thereof; a foam filling member using the same filling foam composition; and a filling foam produced by foaming the filling foam composition.